Wounded Soldier WWI -Hoping to Locate

My grandfather, Donovan Douglas Ellis was a sniper in WWI fighting in France and Belgium.

His battalion (47th Canadian Battalion) took a group of german soldiers prisoner.While stealing a wallet off one of the soldiers, a relative of the german solier pulled a pistol from his boot and was bayonnetted in the neck by my grandfather's sniping partner.This soldier was left for dead.

The soldier survived and caught up with my grandfather in Kelowna, British Columbia Canada and wanted the wallet and pictures contained within back.The man had a prominant scar on his neck. My grandfather gave him some photos but kept some photos and the wallet.On one of the photos (a postcard) is some german handwriting and it is addressed to (illegible first name )"Albrecht", the postcard is postmarked "Warthelager."

I am hoping to return the wallet and photos to the proper family and hopefully someone can point me in the right direction.